Since the initiation of this project in the summer of 1996, considerable progress has been made. We have experienced some delays (approximately 2 months) due to the inability of a software/hardware developer to provide the ordered software and hardware in a timely manner (detailed below) and in recruitment of patients. However, these problems have been solved, and we are proceding rapidly with the clinical phase of the project. The development of the testing battery occupied most of the last half of 1996. This took longer than anticipated due to: 1) Changes that we made in the testing battery and the subsequent need to obtain a custom-built device from a company in Great Britain; 2) The need to pilot a new version of one of the tasks developed exclusively for the study; 3) Acquisition of one of the tasks from another investigator in Great Britain. We have currently recruited and successfully screened 11 Parkinson's disease patients for our current study. Several are currently actively enrolled in the study. The patients have tolerated the drug administration extremely well and no unusual or problematic physical or behavioral side effects have been encountered. We have analyzed the acute phase data from one patient thus far. The data show clear dose-related effects on a number of cognitive operations including motor transit time, internal processing, arousal, motor tracking and the Stroop effect. While it is premature to draw conclusions on the basis of such modest data, we are confident that our battery is sensitive to nicotinic effects. Plans include: 1) Completion of the Parkinson's disease component; 2) Completion of the Spatial Orienting task; 3) Beginning of the Alzheimer's disease component; 4) Data analysis. We anticipate being somewhat behind schedule (approximately 3 months) for the completion of the Alzheimer's disease component of this project, assuming that patient recruitment for the Alzheimer's disease patients goes reasonably well.